What shape do I want the tree to be?
You can lift the crown. This is where you remove the lower branches to create and airy space beneath the tree and a clear trunk. Or, you can clear the crown. This is where you reduce the height of the crown and reduce the number of branches in it, to create a more open structure.
Problems to avoid
Apple trees and fruit trees in general don’t like being near to compost heaps. Avoid compacting the ground around the roots as this damages the tree. Roots can also be damaged by mowers and strimmers, so be careful when cutting nearby. Look to maintain the soil height around the tree and avoid damaging the bark (nails, etc) or constricting the tree trunk in any way (wire, etc).